This invention relates to a watertight connector with improved watertight performance.
As shown in FIG. 5, the applicants of the present application have proposed a watertight connector comprising: a connector housing 3 including receptors (cavities) 3a for inserting and holding terminals 2 fixed to wires 1 therein, and a seal setting portion 3b provided at a rear part of the receptors 3a; a resilient seal member 4 made of a soft material including a front surface 4a making contact with a rear surface 3c of the seal setting portion 3b of the connector housing 3, and press-fit holes 4c formed therein for passing the terminals and the wires for press-fitting; and a holder 5 including a holding portion 5a that makes contact with a rear surface 4b of the seal member 4 to encase the seal member 4, a pair of locking hollows 5b engageable with corresponding projections 3d on the connector housing 3 in a state that the seal member 4 is held between the connector housing 3 and the holder 5, and insertion holes Sc for inserting the terminals and the wires.
In the above watertight connector, as shown in FIG. 6A, the connector housing 3, the seal member 4, and the holder 5 are assembled one another in a state that the seal member 4 is seated in fit contact with the seal setting portion 3b of the connector housing 3, the holding portion 5a of the holder 5 encases the rear surface 4b of the seal member 4 in fit contact therewith, and the projections 3d engage with the locking hollows 5b. 
In this state, after the terminals 2 pass through insertion holes Sc of the holder 5, as shown in FIG. 6B, the terminals 2 are press-fitted in the press-fit holes 4c of the seal member 4 and abutted against lance portions 3e while held by the receptors 3a of the connector housing 3. The wires 1 are press-fitted in the pressfit holes 4c of the seal member 4, and in this way, the outer surface of the wires 1 is sealed in a water-tight state.
Thereafter, as shown in FIG. 6C, when projections 6a of a retainer 6 are thrust into the receptors 3a from the front side of the connector housing 3, the tip ends of the projections 6a are abutted against the tip ends of the lance portions 3e to thereby hinder the retainer 6 from being further thrust any more. This is a half-fitted state where the terminals 2 are in incomplete engagement with the lance portions 3e. Further thrusting the terminals 2 from the rear side of the connector accomplishes a complete engagement with the lance portions 3e. 
When the projections 6a of the retainer 6 are completely thrust into the receptors 3a, the projections 6a engage with the lance portions 3e so that the lance portions 3e may not be deflected. Thus, the terminals 2 are prevented from loosening off from the connector.
In the above conventional watertight connector, the terminals 2 and the wires 1 are required to be altogether press-fitted in the press-fit holes 4c of the seal member 4. Accordingly, it is highly likely that part of the seal member 4 around the press-fit holes 4c may be damaged or scraped off due to forcible insertion of the tubular terminals 2 each having a rectangular shape in cross-section into the press-fit holes 4c and that the scraped part may be intruded inside the terminals to thereby cause an electrical problem resulting from inferior contact of the connector.
Another problem may rise from the following construction of the above watertight connector. Each of the terminals 2 is provided with a stabilizer 2a projecting outward on a lateral side thereof as a mark for preventing a possibility that the terminals 2 may be inserted upside down. Since the press-fit hole 4c has, as shown in detail in FIG. 7A, a smaller dimension than the outer configuration of the terminal 2 viewed from the front side, it is highly likely that the edge-shaped stabilizer 2a may damage the press-fit hole 4c while the terminal 2 being pressingly inserted in the press-fit hole 4c to thereby impair the sealability of the watertight connector around a portion where the wires are inserted. The above problem must be considered also in the case where the press-fit holes 4c have a slit-like shape, as shown in FIG. 7B.
In view of the above problems residing in the prior art, it is an object of this invention to provide a watertight connector with improved watertight performance at a portion where a connector housing and wires are provided.
To solve the above problems, according to an aspect of this invention, this invention is directed to a watertight connector comprising: a connector housing formed with receptors for inserting and holding terminals connected to wires therein, and a seal setting portion provided at a rear part of the receptors; a resilient seal member made of a soft material including a front surface made in contact with a rear surface of the seal setting portion and formed with segment holes for inserting the terminals and the wires therein; and a holder including a pressing portion made in contact with a rear surface of the seal member to compress the seal member forward, a locking part engageable with the connector housing when the seal member is compressed, and insertion holes for inserting the terminals and the wires therein. The watertight connector has the features that the seal setting portion of the connector housing is formed with a housing recess for housing the seal member therein, and that the seal member is compressed by the pressing portion of the holder when the seal member is housed in the housing recess in a state that the terminals connected to the wires pass through the insertion holes of the holder and the segment holes of the seal member and are held in the receptors of the connector housing.
According to this invention, the seal member is housed in the housing recess of the seal setting portion of the connector housing, and the terminals connected to the wires pass through the insertion holes of the holder and the segment holes of the seal member and are held in the receptors of the connector housing, whereby the seal member is compressed by the pressing portion of the holder. Consequently, the segment holes of the seal member reduce the respective sizes thereof due to the compression so as to deform in conformity with the outer shape of the wires.
In this way, when the seal member is housed in the housing recess defined in the seal setting portion of the connector housing and compressed by the pressing portion of the holder, the front surface of the seal member makes fit contact with the rear surface of the seal setting portion, and the outer surface of the seal setting portion makes fit contact with the inner surface of the housing recess. Thus, the sealable contact area of the seal member with the connector housing increases to secure sealability of the connector at the connector housing portion.
Further, as the compression of the seal member reduces the sizes of the segment holes, the seal member is deformed into such a shape as to follow the outer shape of the wires. Thus, secured is the sealability of the connector at a portion where the wires are inserted.
There is an idea of forming a housing recess in a front surface of a pressing portion of a holder in place of forming the housing recess in the seal setting portion of the connector housing. In this case, the seal member is set in the housing recess of the holder. This arrangement may cause a problem that the sealable contact area of the seal member with the connector housing decreases because the contact of the seal member with the connector housing is limited to the contact of the front surface of the seal member with the rear surface of the seal setting portion of the connector housing without a fit contact of the outer surface of the seal member with the connector housing. This arrangement is liable to result in an insecure sealed state of the connector at the connector housing portion.
In order to prevent the above-stated problem, there is an idea of increasing the front area of the seal member. This, however, would enlarge the outer configuration of the seal member and undesirably result in large-sized holder and connector housing.
Also, the above idea of forming the housing recess in the holder results in that the seal member is set on the side of the holder when the connector is assembled. When the terminals connected to the wires pass through the insertion holes of the holder and the segment holes of the seal member and are held in the receptors of the connector housing, this arrangement may cause the following problem. Specifically, when attempting to insert the terminals connected to the wires in the segment holes of the seal member with this arrangement, the terminals may deform the seal member toward the connector housing where the seal setting portion is provided if there should remain a clearance between the front surface of the seal member and the rear surface of the connector housing where the seal setting portion is provided, thereby making the insertion operation difficult and causing an insecure sealed state of the connector where the wires are inserted.
According to another aspect of this invention, each of the segment holes of the seal member may have such a size as to make free from intervening of the insertion of the terminals. With this arrangement, there is no possibility of forcibly widening the segment holes when the terminals are inserted in the segment holes of the seal member. The resistance exerted to the seal member and the wires at the time of insertion reduces, thereby lowering a possibility of bending the terminals during the insertion operation and accordingly improving the insertion operability. Particularly, a watertight connector provided with multipoles is constructed such that signal circuits occupy primary part of the connector due to its characteristic that the connector is used as a part of an electronic unit. Accordingly, this arrangement is effective in preventing lowering insertion operability of the connector of multipolar type.
Also, there is no possibility that stabilizers of the terminals would scrape off or impair part of the seal member around the segment holes when the terminals. are inserted in the segment holes of the seal member. Accordingly, prevented is deterioration of sealability of the connector at a portion where the wires are inserted, and watertight performance thereof is improved.
According to still another aspect of this invention, preferably, each of the segment holes of the seal member may have such a size as to enable insertion of a plurality of terminals side by side in a row. With this arrangement, there is no need of molding a partition wall with a very small thickness in the seal member due to a small interval between the adjacent insertion holes of the seal member. Thereby, molding of the segment holes in the seal member is facilitated.
According to yet another aspect of this invention, the insertion holes of the holder may be so formed as to correspond to the receptors of the connector housing. Provided that the dimension of the insertion holes of the holder should be set so large as to enable insertion of the plurality of terminals side by side in correspondence with the size of the segment holes of the seal member in addition to the structure that each of the segment holes of the seal member is so formed as to enable insertion of the plurality of terminals side by side in a row, such an arrangement would undesirably allow the seal member to deform into the shape of the large insertion holes of the holder when being compressed, thereby hindering effective compression of the seal member. Further, such an arrangement would make it impossible to accurately hold the position of the receptors of the connector housing at the time of terminal insertion and thus make it impossible to accurately insert the terminals in the receptors of the connector housing through the insertion holes of the holder and the segment holes of the seal member. The preferred arrangement, however, would eliminate such a problem.
According to still further aspect of this invention, preferably, a front surface of the holder may be formed, at positions corresponding to the segment holes, with indents to receive a part of the press-deformed seal member when the holder is engaged with the connector housing. With this arrangement, as the part of the seal member is intruded in the indents when the seal member is compressed, the segment holes of the seal member are further deformed in conformity with the outer shape of the wires, thereby furthermore enhancing watertight effect of the connector where the wires are provided.